Method for deploying a device to a distal location across a diseased vessel

ABSTRACT

Configurations are described for assisting in the execution of a percutaneous procedure while protecting the vascular pathway to the operational theater, which may comprise diseased tissue. A railed sheath may be utilized which is controllably expandable and collapsible, and may comprise two or more elongate rail structures configured to assist in the distribution of loads to associated diseased tissue structures, while also contributing to the deployment of percutaneous tools by maintaining alignment of such tools with the railed catheter and associated anatomy.

RELATED APPLICATION DATA

The present application claims the benefit under 35 U.S.C. §119 to U.S.Provisional Application Ser. No. 61/558,397 filed Nov. 10, 2011; U.S.Provisional Application Ser. Nos. 61/558,357 filed Nov. 10, 2011; andU.S. Provisional Application Ser. No. 61/717,575 filed Oct. 23, 2012.The foregoing applications are hereby incorporated by reference into thepresent application in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to medical interventionsconducted through vessels such as the major arteries, and moreparticularly to access and deployment configurations for conductingpercutaneous procedures such as percutaneous valve replacement.

BACKGROUND

Gaining access to the heart is a continued challenge in cardiovascularmedicine. Conventional procedures for accomplishing tasks such as valvereplacement generally involve a thoracotomy and/or creation of one ormore access ports across the wall of the heart itself, which isrelatively highly invasive and therefore undesirable. Recent progresshas been made in the area of percutaneous intervention, whereininstrumentation, such as catheters, guidewires, and prostheses, arebrought to the heart through the vessels connected to the heart. One ofthe challenges with percutaneous approaches to procedures such as valvereplacement, is that patients with diseased valves often have diseasedmajor vessels, and the instrumentation required to accomplish aprocedure such as a percutaneous valve replacement is often fairlylarge. For example, the un-expanded delivery size of a CoreValve (®)aortic valve prosthesis available from Medtronic, Inc. is approximately18 French; the un-expanded delivery size of a Sapien (®) valve availablefrom Edwards Lifesciences, Inc. is between 18 and 24 French, dependingupon which size is utilized. Such outer sizes do not allow for aconventional guide catheter to be inserted as a protective layer betweenthe tools and the tissue, and therefore the standard of care has becomedirect insertion of the valve instrumentation through the diseasedvessels to reach the target location within or adjacent to the heart.Another complicating factor with such interventions is the fact that itis likely that the aorta through which the devices will be advanced willbe diseased (one recent study concluded that 61% of patients over 65years of age severe aortic valve stenosis also have severe aorticatherosclerosis; Osranek et al., American Journal of Cardiology, 2009;103: 713-717). FIG. 1 illustrates a typical diseased aorta (2) withdeposits (4) clinging to almost all interior surfaces. This complicatedsurgical paradigm has lead some clinical researchers to believe thatelevated stroke rates associated with such procedures may be related tothe physical insertion of large interventional tools through diseasedvessels and concomitant scaping or microscraping action of the toolsagainst the diseased vessel walls, which is breaking portions of plaqueloose and allowing these to flow with the bloodstream into the brain andother undesirable landing places. There is a need for a configurationwherein a relatively thin but protective sheath-like member can be putin place to guide the interventional tools and prosthesis whilemitigating load concentrations and/or scraping or abrasion of theinterior of the subject vessels. The subject invention is directed toaddress such need.

SUMMARY

One embodiment is directed to a method for deploying a device to adistal location across a diseased vessel, comprising inserting a railedexpandable sheath into a diseased vessel at a point of entry, the sheathdefining a lumen therethrough and comprising two or more longitudinalrail structures coupled to a sheetlike member, the sheath having acollapsed configuration, wherein the sheath has a first cross sectionalouter diameter defines a first lumen inner diameter, and an expandedconfiguration, wherein the sheath has a second cross sectional outerdiameter and second lumen inner diameter, such that in the collapsedconfiguration, the sheath is configured to be advanced across at least aportion of the diseased vessel to a position adjacent the distallocation without substantial size interference between the first crosssectional outer diameter of the sheath and an inner diameter profile ofa lumen of the diseased vessel; and upon positioning the collapsedconfiguration to the desired position relative to the distal location,the sheath may be expanded to the expanded configuration withincremental pushing of a device longitudinally through the lumen suchthat loads imparted upon the sheath by the device are transferred to therails and distributed to nearby portions of the diseased vessel in adeconcentrated and nonabrasive manner; inserting the device through thelumen to transform the sheath into the expanded configuration. Themethod further may comprise deploying an emboli filter into the diseasedvessel at a location opposite of the sheath point of entry from thedistal location. The method further may comprise deploying one or moreemboli filters into the diseased vessel to capture emboli which may exitthe diseased vessel to associated tributary vessels. The method furthermay comprise observing one or more radioopaque markers which may becoupled to one or more locations upon the sheath using fluoroscopy whileinserting the railed expandable sheath, the markers being configured tobe associated with a designated anatomical structure comprising thediseased vessel. The sheetlike member may comprise one or more porousregions configured to allow blood to flow from a position within thelumen to a position across the sheetlike member and outside of thesheath, and inserting may comprise positioning the one or more porousregions adjacent one or more anatomical structures. The one or moreporous regions may be configured to be aligned with tributary vesselsthat join the diseased vessel. The method further may comprise examininga flow pattern adjacent the sheath and designated anatomical structureusing Doppler ultrasonic analysis. The ultrasonic analysis may beconducted using a transcutaneous ultrasound transducer. The ultrasonicanalysis may be conducted using an intravascular ultrasound transducerwhich may be coupled to an elongate probe configured to be placedthrough the lumen of the sheath. Inserting the device may comprisepressing one or more surfaces of the device against exposed portions ofthe rail structures of the sheath to move the rail structures away fromeach other into the expanded configuration as the device is advanced.The method further may comprise inserting a balloon dilatation probeinto the lumen to complete the reconfiguration of the railed expandablesheath from the collapsed configuration to the expanded configuration.The railed expandable sheath may be self-expanding from the collapsedconfiguration to the expanded configuration, and the method further maycomprise removing a removable expansion retention member configured toretain the railed expandable sheath in the collapsed configuration. Theexpansion retention member may comprise a corset and tensile memberassembly, and the method further may comprise tensioning the tensilemember proximally to release the corset and allow expansion to theexpanded configuration. The method further may comprise inserting aguidewire through the diseased vessel and using the guidewire to assistwith guiding the sheath by advancing the lumen over the guidewire. Oneor more portions of the rail structures may comprise a ferromagneticmaterial, and the method further may comprise passing a magnetic probethrough the lumen of the expanded configuration to assist withaffirmative collapsing of the sheath back to the collapsedconfiguration. One or more portions of the rail structures may comprisea ferromagnetic material, and the method further may comprise retaininga magnetic probe through the lumen of the expanded configuration tomaintain the collapsed configuration until transformation to theexpanded configuration is desired. The method further may compriseretracting the sheath out of the point of entry. Inserting the railedexpandable sheath may comprise manually manipulating a proximal portionof the sheath to advance the sheath into the diseased vessel. Insertingthe railed expandable sheath may comprise manually advancing an elongateprobe that is coupled to the railed expandable sheath relative to thediseased vessel. The sheath may comprise two diametrically opposed railstructures coupled to the sheetlike member. The sheath may comprisethree rail structures distributed circumferentially equidistantly. Thesheath may comprise four rail structures distributed circumferentiallyequidistantly. The first lumen inner diameter may be equal to betweenabout 0 mm and about 3 mm. The second lumen inner diameter may be equalto between about 6 mm and about 8 mm. The rail structures may comprise amaterial selected from the group consisting of: polyethylene,ultra-high-molecular weight polyethylene, polyethylene terepthalate,polyoxymethylene, polytetrafluoroethylene, and co-polymers thereof. Therail structures may comprise nitinol alloy. The rail structures may becoated with a lubricious coating. The sheetlike member may comprise amaterial selected from the group consisting of: polyethylene,polytetrafluoroethylene, and co-polymers thereof. The diseased vesselmay be an aorta. The device may be an implantable prosthesis. Theimplantable prosthesis may be a cardiac valve. The distal location maybe a location within a heart coupled to the diseased vessel. The sheathmay be placed across substantially the full length of the aorta betweenthe point of entry and a heart coupled to the aorta. The sheath may beplaced across only a portion of the length of the aorta between thepoint of entry and a heart coupled to the aorta. The sheath may beplaced up to, but not across, the carotid artery takeoffs from theaorta. The point of entry may be in a femoral artery coupled to theaorta, and the first cross sectional outer diameter may be configured toaccommodate insertion through the femoral artery. Expanding the sheathto the expanded configuration may comprise unwinding a built up twistingconfiguration that has been created to maintain the collapsedconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B illustrate various portions of a diseased aorta.

FIGS. 2A-2F illustrate aspects of a conventional interventional devicedeployment through a diseased aorta.

FIGS. 3A-3Z-4 illustrate various aspects of an inventive expandablerailed sheath that may be used in conducting various cardiovascularprocedures, such as a percutaneous aortic valve replacement procedure.

FIGS. 4A-4H illustrate aspects of a configuration similar to that ofFIGS. 3A-3Z-4, wherein a branch vessel protection filter is alsoincorporated.

FIGS. 5A-5K illustrate aspects of a configuration similar to that ofFIGS. 3A-3Z-4, wherein a tubular branch vessel protection filter is alsoincorporated.

FIG. 6 illustrates a configuration wherein a magnetic probe is utilizedto collapse a sheath after an intervention has been conducted through anexpanded form of the sheath.

FIG. 7 illustrates a configuration wherein a magnetic probe is utilizedto retain a sheath in a collapsed form until an expansion to an expandedform is desired.

FIGS. 8A-8G illustrate aspects of a configuration similar to that ofFIGS. 3A-3Z-4, wherein a distal protection filter is also incorporated.

FIG. 9 illustrate aspects of a configuration similar to that of FIGS.3A-3Z-4, wherein only a proximal portion of the main vessel is protectedby an embodiment of the inventive sheath.

FIG. 10 illustrates various aspects of a deployment technique inaccordance with the present invention.

FIG. 11 illustrates various aspects of a deployment technique inaccordance with the present invention.

FIG. 12 illustrates various aspects of a deployment technique inaccordance with the present invention.

FIG. 13 illustrates various aspects of a deployment technique inaccordance with the present invention.

FIG. 14 illustrates various aspects of a deployment technique inaccordance with the present invention.

FIG. 15 illustrates various aspects of a deployment technique inaccordance with the present invention.

FIG. 16 illustrates various aspects of a deployment technique inaccordance with the present invention.

FIGS. 17A-17C illustrate aspects of an embodiment of a railed sheathhaving a frustoconical distal portion configured to interface with acardiovascular cavity.

FIGS. 18A-18J illustrate various aspects of an inventive expandablerailed sheath that may be used in conducting various cardiovascularprocedures, such as a percutaneous aortic valve replacement procedure.

FIG. 19 illustrates various aspects of a deployment technique inaccordance with the present invention.

DETAILED DESCRIPTION

Referring to FIG. 1B, an illustrative representation of a diseased aorta(2) is shown with deposits (4) distributed in several locations,including adjacent or within the left (6) and right (8) iliac arteries,and adjacent the junctions of the aortic arch with the left subclavian(10), left common carotid (12), and innominate artery (14). Navigating adiseased aorta (2) such as that depicted is indeed a challenge withconventional intravascular diagnostic and/or interventional hardware.For example, referring to FIGS. 2A-2F, a conventional instrumentdeployment is illustrated to demonstrate the disease-related challenges.Referring to FIG. 2A, the elongate instrument (46) is advanced in aretrograde direction through the aorta (2) distal tip (50) first. Theinstrument (46) may be a valve deployment member or probe, a catheter orconduit for conducting various interventions, etc. Referring to FIG. 2B,as the instrument (46) is advanced farther toward the targeted anatomy,the distal end (50) may become a scraping interface (48) as it is urgedpast and against the tissue comprising the diseased aorta (2), and mayaccidentally and undesirably cause one or more pieces of the depositmaterial (4) to become loose and thereby flowing distally-perhaps intothe brain or another undesirable deposit flow location. Further, thescraping dynamic between the distal tip (50) of the instrument (46) andthe aortic tissue may result in the formation of one or more embolicmasses, which also may find themselves undesirably drifting with theflow path toward the brain or other tissue. FIG. 2C shows that at therelatively extreme turning portions of the aortic arch, a conventionalinstrument may find itself located immediately adjacent or within thetakeoff junctions of the joining arteries (10, 12, 14), where plaquesand other deposits may be particularly mechanically vulnerable. FIGS.2D-2F illustrate further advancement of the instrument (46) until thedistal tip (50) is in the desired location for the planned diagnostic orinterventional procedure. Subsequently, the instrumentation is typicallyretracted, causing yet another scraping interface type of interaction asthe instrumentation is pulled proximally in a pathway opposite to thatdescribed in reference to FIGS. 2A-2F, and additional risks forundesirable complication related to such interaction.

Referring to FIGS. 3A-3Z-4, various aspects of deployment steps andconfigurations utilizing embodiments of the inventive expandable railedsheath are illustrated. Referring to FIG. 3A, a collapsed configuration(16) of a railed sheath is being inserted (80) distal tip (52) first.This collapsed configuration (16) may be inserted over a guidewire usingconventional “over-the-wire” technique to assist in guiding thecollapsed sheath configuration. As compared with the insertion scenarioof, for example, FIG. 2A, the collapsed configuration (16) leaves muchmore room in the diseased aorta (2), thereby decreasing the likelihoodof a scraping type mechanical interface relationship as described inreference to FIGS. 2A-2F above. In one embodiment, the railed sheath maycomprise one or more pullwires to facilitate steering by an operator asthe collapsed railed sheath (16) is advanced through the diseased aorta(2) using imaging modalities such as transcutaneous ultrasound and/orfluoroscopy to assist with the interactive steering of suchconfiguration through the diseased vessel. Referring to FIG. 3B, thedistal tip (52) of the collapsed configuration (16) has reached thedesired interventional location (here the aortic outflow tract of theleft ventricle cavity of the heart) in a minimally invasive way takingadvantage of the relatively small cross sectional size of the collapsedconfiguration (16). Referring to FIGS. 3C and 3D, close up views of thecollapsed configuration (16) are illustrated to show that the railedsheath indeed comprises a plurality of elongate rail structures (20; inthe depicted embodiment 4 independent rail structures) coupled togetherby a sheet or sheetlike member (22) which, in the depicted collapsedconfiguration (16) is folded in between the elongate rail structures(20). A lumen (24) is defined through the railed sheath, and remainsrelatively small in diameter with the collapsed configuration (16).

Referring to FIGS. 3E-3Q, various configurations of railed sheathembodiments are illustrated in cross sectional views. One key corefunctionality of each of the illustrative embodiments described hereinis the notion of protecting surrounding vascular and other anatomy byproviding an intermediate surface between relatively large items to bemoved through the vasculature (i.e., such as elongate tools, collapsedprostheses, etc) and the vasculature itself. The intermediate surface,or protective sheath, generally comprises a sheetlike member that isreinforced by a plurality of generally longitudinal rail members thatare configured to de-concentrate loads applied from the inside of thesheath toward the nearby vascular anatomy-in a manner somewhat akin tothe manner in which point loads from train wheels on a railroad trackare de-concentrated by the rails of the railroad track and absorbed overa large surface provided by the substrate underlying the railroad track.This load de-concentration is believed to provide protection of theunderlying anatomy from focused loads that could dislodge plaques orother particles, or create emboli—either from the focused load interfaceitself, or from any scraping or abrading interfacing that may be relatedto conventionally pushing a piece of hardware past the unprotectedanatomy, as in FIGS. 2A-2F. Referring to FIG. 3E, an expanded form (26)of a railed sheath embodiment is shown having four elongate rail membersdistributed approximately equidistantly about the circumference of theexpanded form (26). The expanded form has an approximately circularouter shape and defines an approximately circular inner lumen. Theelongate rail structures themselves have elliptical cross sectionalshape profiles (20) configured to atraumatically and easily accommodatesliding of another diagnostic or interventional device through the lumenduring a medical procedure such as a percutaneous valve replacement.FIG. 3F illustrates one configuration of the same hardware as shown inFIG. 3E, but in the compressed or collapsed (16) format, with thesheetlike member (22) folded in both directions (i.e., partially foldedonto each of the immediately adjacent rail structures 20). FIG. 3Gillustrates another configuration wherein the sheetlike member (22) isfolded in one direction (i.e., to find mechanical support for slackportions on the next adjacent rail structure 20 in one direction asshown). Either of the collapsed configurations illustrated in FIGS. 3Fand 3G, for example, may be suitable for deployment as in FIGS. 3A and3B. Referring to FIGS. 3H-3M, various expanded configuration (26)embodiments are depicted to illustrate that a great variety ofcombinations and permutations of hardware subcomponentry is within thescope of the invention. Referring to FIG. 3H, four elliptical railstructures (20) are coupled to the outer aspect of a substantiallytubular sheetlike member (22), for example, with polymer welding,adhesive, suturing, or other coupling configuration. The outer aspectsof such configuration may be coated with a lubricious polymer to assistin the ease of sliding such a configuration past nearby tissuestructures in a collapsed state; similarly, the inner aspects may becoated with a lubricous coating or surface to assist with slidableengagement between the expanded state of the railed sheath andinstruments which may be passed through the working lumen duringdiagnostic and/or interventional procedure steps. Referring to FIG. 3I,in one embodiment, elongate rail structures of circular cross section(32) may be utilized for a more uniform bending modulus configuration,and referring to FIG. 3J, elongate rail structures of rectangular orsquare cross section (34) may be utilized to present preferred bendingaxes to the overall structure of the railed sheath. Referring to FIGS.3K-3M, embodiments similar to those illustrated in FIGS. 3H-3J aredepicted, with exception that the embodiments of FIGS. 3K-3M have theelongate rail structures (20, 32, 34, respectively) more tightlyintegrated into the outer and inner shape of the overall structure(i.e., the outer aspects of the rail structures don't protrude out asmuch). This may be accomplished, for example, by co-forming the rails(20, 32, 34, respectively) from the same bulk material as the sheetlikemembers (22), or at least partially encapsulating the rails (20, 32, 34,respectively) with the sheetlike member (22) material. Referring back tothe embodiment of FIG. 3E, various embodiments may be created to have asubstantially smooth outer shape in the expanded state, and to have theelongate rail structures (20) protrude more into the inner lumen of theoverall structure, which may be desired for mechanically guiding variousportions of the diagnostic and/or interventional hardware that may bepassed through the working lumen for the medical procedure.

Referring to FIGS. 3N-3Q, various configurations are shown to illustratethat cross sectional homogeneity is not only not necessary, but may notbe preferred in some scenarios. Referring to FIG. 3N, one expandedconfiguration (26) is shown wherein a sheet like member (22) couples twoelliptical rail structures (20) and two circular rail structures (32).

Referring to FIG. 30, a less cross sectionally homogeneous configurationis shown having two elliptical rail structures (20) coupled to thesheetlike member (22) diametrically across from each other, and acircular rail structure (32) diametrically opposed from a rectangular(34) rail structure at an angle so that the four depicted railstructures are not uniformly distributed about the circumference of thedepicted cross section. Referring to FIG. 3P, three rectangular railstructures (34) are equidistantly circumferentially distributed aboutthe cross section. Referring to FIG. 3Q, a group of triangular (36),elliptical (20), and rectangular (34) rail structures is notequidistantly circumferentially distributed about the cross section. Thevarious cross sectional permutations and combinations may be selected toimprove deliverability, to have selected overall shape bending moduli,and to improve utility of the working lumen for passing throughdiagnostic and/or interventional tools during a medical procedure.

Further, the mechanical performance of the collapsible railed sheath maybe customized and modified by changing the shapes, materials, andpositions/orientations of various portions longitudinally (i.e.,relative to the length of the overall catheter structure). Several suchconfigurations are illustrated in FIGS. 3R-3V. Referring to FIG. 3R, alongitudinally uniform configuration has the same cross sectionalconfiguration of rail structures (20) and sheetlike member (22) allalong its length. Referring to FIG. 3S, an embodiment is shown whereinthe outer shape of the overall structure does not change longitudinally,but wherein one or more of the rail structures (20) are tapered in shape(38) longitudinally, to provide greater overall bending modulus for thecatheter at the end with the more tapered rail structures. Referring toFIG. 3T, an embodiment is depicted which has not only one or moretapered (38) rail structures (20), but also a tapered (40) overall outershape. Such a configuration would have inner lumen size limitations, butwould provide greater overall bending modulus for the catheter at theend with the more tapered rail structures and overall shape. Referringto FIGS. 3U and 3V, the rail structures may be angularly orientedrelative to the longitudinal axis of the overall shape. As shown in theexpanded configuration (26) of FIG. 3U, one or more of the railstructures (20) have a spiral orientation (42). FIG. 3V shows that thesame embodiment as shown in FIG. 3U may be collapsed into a collapsedconfiguration (16), with the spiral orientation (42) of the one or morerail structures retained, but to a lesser spiraling angle relative tothe longitudinal axis of the overall shape.

Referring to FIGS. 3W and 3X, the transition between collapsedconfiguration (16) and expanded configuration (26) may be accomplishedby advancing a diagnostic and/or interventional instrument (44) throughthe lumen of the railed sheath. As shown in FIG. 3W, the proximalportion of the railed sheath through which the instrument (44) has beenadvanced are in the expanded configuration (26), while the distalportion which has not yet been reached by the instrument (44) remains inthe collapsed configuration (16). In one embodiment, the rails arespecifically configured to assist in maintaining the orientation of theinstrument (44) relative to the railed sheath and associated tubularanatomy as the instrument (44) is advanced through the railed sheath, toensure that a predictable orientation is maintained when the instrument(44) reaches the desired diagnostic and/or interventional tissuetheater. For example, in the case of a percutaneous valve replacementprocedure, it is highly desirable to make sure that the valve prosthesisgets to the desired location, such as in the aortic outflow tract, in apredictable orientation relative to the structural tissue of the outflowtract, but also that damage is not caused to the patient during thedeployment; the subject configurations are designed with such prioritiesin mind. In another embodiment, as described in further detail below,the railed sheath may be a self-expanding sheath that is affirmativelyretained in a collapsed configuration (16) until a desired time uponwhich it may be controllably converted to the expanded configuration(26). A corset-style collapse-retention member with a releasable (i.e.,by proximal tension) tensile member may be utilized to retain thecollapsed configuration, as in International PCT Publication No. WO97/21403, which is incorporated by reference herein in its entirety.

Referring to FIG. 3Y, in one embodiment, an expanded configuration of arailed sheath (26) may comprise one or more porous regions (132)configured to be positioned adjacent tributary vessels to maintain flowthrough such vessels when the expanded railed sheath is in place. Asshown in FIG. 3Y, a porous region (132) is configured in this embodimentto ensure that flow coming into the distal tip (52) of the expandedrailed sheath (26) is at least partially diverted up the associatedtributary vessels (10, 12, 14) to supply with brain of the patient withblood during the procedure. The margins of the porous region may bemarked with radioopaque markers to facilitate confirmation of placementof the porous region in a desired configuration relative to the anatomy,and transcutaneous and/or intravascular ultrasound and/or fluoroscopywith contrast agent may be utilized to confirm flow out of the aorta andinto important tributary vessels during placement of the railed sheath.Preferably the porous region functions not only as a flow bypass, butalso as a filter to capture any deposits or emboli that are being routedthrough the railed sheath; this may be accomplished by sizing the poresof the porous region to be large enough to pass blood plasma and redblood cells, but small enough to not pass typical emboli and deposits.Referring ahead to FIGS. 17A-17C, an embodiment similar to that of FIG.3Y is depicted, but in this case the distal end of the railed sheathcomprises a trumpet or frustoconical shape (140) configured to maximizethe likelihood that emboli or deposits that exit the adjacent anatomy(here the aortic outflow tract of the left ventricle cavity of the heart138) by providing a more contoured fit of the adjacent anatomy.Referring to FIG. 17B, during deployment, the flared distalfrustoconical portion (140) may be retained in a compressed form by amovable or slideable cuff member (142), which, as shown in FIG. 17C, maybe retracted (144) proximally to allow the flared distal frustoconicalportion (140) to be expandable or expanded (146) into the adjacentanatomy.

In both FIG. 17A and 3Y, an elongate insertion device (56) is showninserting a diagnostic and/or interventional device (54), such as acollapsed aortic valve prosthesis, toward the desired anatomicallocation using the subject railed sheath. Referring to FIGS. 3Z, and3-Z1 with the device (56) safely deployed into the subject anatomy, theelongate insertion device (56) may be safely retracted (58) back outthrough the expanded configuration (26) of the railed sheath. Referringto FIG. 3-Z2, with the diagnostic and/or interventional proceduresubstantially completed, the railed sheath may be removed by pullingproximally (60) on the sheath and retracting it out, as shown in FIGS.3-Z3 and 3-Z4. In another embodiment, as described in further detailbelow, the sheath may be forcibly converted from expanded configuration(26) to collapsed configuration (16) for removal, using, for example, anelectromagnetic collapsing device. With all of the instrumentationremoved, the access wound (for example, to one of the femoral arteries)may be closed and the procedure completed.

Referring to FIGS. 4A-4H, in one embodiment a separate filtering device,such as that sold under the tradename Embrella (®) by EdwardsLifesciences, Inc., may be utilized to assist in preventing unwantedparticles or emboli from entering certain tributary vessels. Referringto FIG. 4A, a collapsed filtering device (68) may be advanced (62) withan elongate deployment member (66). Referring to FIG. 4B, the filteringdevice may be converted to an expanded configuration (70) wherein one ormore wings (72, 74) form filtrating barriers across one or moretributary vessels (12, 14) and are temporarily retained in place by aretainer member (76). Referring to FIG. 4C, the deployment member (66)may be retracted (78), and as shown in FIG. 4D, a collapsed railedsheath configuration (16) may be advanced (80). Referring to FIG. 4E,the collapsed railed sheath configuration (16) may be utilized as inreference to FIGS. 3A to 3Z-4 above, but with the temporary filterdevice in place. After the railed sheath has been utilized for adiagnostic and/or interventional procedure, it may be removed, and anelongate recapture device (56) may be inserted (62) to recapture thefiltration device (64), as shown in FIGS. 4F and 4G, followed byretraction (58) and completion of the case.

Referring to FIGS. 5A-5K, in another embodiment, a tubular filter may bedeployed before installation of a railed sheath to assist with filteringprotection at one or more tributary vessel junctions. Referring to FIG.5A, an elongate deployment member (88) removably coupled to a collapsedtubular filter (84) may be advanced (90) toward the anatomic location ofinterest, using, for example, fluoroscopic and/or ultrasound imagingguidance, which may be assisted by radioopaque markers on the filter(84) and/or deployment member (88), and/or the injection of imagingcontrast agent. Referring to FIG. 5B, with the collapsed tubular filter(84) in the desired longitudinal position, the tubular filter may beconverted to the expanded configuration depicted in FIG. 5C, using, forexample, a balloon expansion element of the deployment member, or arelease of a constraining member that retains a self-expandingconfiguration of the tubular filter until expansion is desired, afterwhich the restraint is released and expansion ensues to the expandedconfiguration (86) of the tubular filter, which is configured to screenemboli and/or unwanted particles from entering the associated tributaryvessels (10, 12, 14 in the depicted example). The deployment member (88)may be removed (92), as shown in FIG. 5D, and a collapsed railed sheathconfiguration (16) may be inserted (80) through the expanded tubularfilter (86), as shown in FIGS. 5E and 5F, to conduct a procedure insimilar fashion as described above in reference to FIGS. 3A to 3-Z4 (inone embodiment the porosity of the porous portion (132) may be increasedto maximize flow, since an additional filter is already in place; inanother embodiment the porous portion (132) may simply comprise an openwindow section of the railed sheath). Referring to FIG. 5G, with theprocedure coming to completion, the railed sheath (26) may be removed(60), and as shown in FIG. 5H, the filter deployment member (88) may beadvanced to recapture the filter and pull it proximally out (92),causing it to slightly collapse and become mobile relative to theanatomy. Referring to FIG. 51, in another embodiment, two or morepullwires (94, 96) may be coupled to the tubular filter (eitherintraoperatively, or preoperatively and left in place during theprocedure with leads to a proximal manual access point) and utilized toforcibly dislodge the tubular filter for withdrawal by causing radialcollapse of at least a proximal portion (98) of the tubular filter (86)as it is pulled toward the small aperture of the deployment member (88)through which the pullwires or tether lines (94, 96) exit to couple tothe filter. Referring to FIG. 5J, in another embodiment, a distalportion of an electromagnetic deployment probe (100) may be configuredto controllably attract ferromagnetic portions of the tubular filter todraw the filter back into a collapsed state when a voltage source (104)provides electromagnetic attraction toward one or more electromagnetscoupled to the distal portion (102) of the electromagnetic deploymentprobe (100). Referring to FIG. 5K, the tubular filter may be retractedand removed.

Referring to FIG. 6, a deployment probe (106) with a longerelectromagnetic portion than that of FIG. 5K may be utilized to assistin the affirmative re-collapsing of a railed sheath embodiment thatcomprises ferromagnetic portions which may be controllably attractedtoward the electromagnetic deployment probe (106) using an operativelycoupled voltage controller (108). In one embodiment, the voltagecontroller (108) may be configured to activate all of the electromagnetson the probe (106) simultaneously to re-collapse the associated lengthof the railed sheath simultaneously. In another embodiment, thecontroller (108) may be configured to sequentially activate (and retainactivation until release is desired) the various electromagnetscomprising the probe to provide for a sequential longitudinal collapsingof the associated railed sheath (i.e., from the most proximal portion tothe most distal portion, vice versa, etc).

Referring to FIG. 7, a deployment probe (106) similar to that depictedin FIG. 6 may be utilized to forcibly retain a collapse configurationuntil sequential or simultaneous expansion of all portions of the railedsheath is desired. In other words, the magnet controller (108) may beconfigured to retain the collapsed state of the entire exposed length ofthe railed sheath during insertion. When the desired longitudinalpositioning has been accomplished, the magnet controller may beconfigured to either simultaneously or sequentially release portions ofthe railed sheath to allow for expansion to the expanded form (26).Completion of expansion to the expanded form (26) may be completed as aresult of a self-expanding infrastructure of the railed sheath, with thehelp of an expandable balloon, etc.

Referring to FIGS. 8A-8G, a proximal filter, or “distal protectiondevice”, may be placed proximal to the access point for theaforementioned hardware embodiments to prevent particles or emboli fromflowing distally. Referring to FIG. 8A, a close up view of an accesspoint (110, such as an arteriotomy) and associated vessels (6, 8) anddeposits (4) is shown with a collapsed filtration device (112) beingadvanced (116) with a deployment member (114) through the access point(110). Referring to FIG. 8B, the deployment member (114) may be shapedsuch that the collapsed filtration device (112) can be tuckedimmediately proximal of the access point (110). As shown in FIG. 8C, thefiltration device may be self expanding or expandable (i.e., with aballoon) to be controllably converted into an expanded/deployedconfiguration (120) wherein blood flow (124) is directed across a filtermesh (112) portion of the expanded filter (120) to prevent passage ofemboli, particles, and the like. Preferably the filter (120) has atether member (126) which may be extended out of the access point (110)and used subsequently for recapture and removal of the filter. Referringto FIGS. 8D and 8E, with the expanded filter (120) in place, a collapsedrailed sheath (16) may be advanced and utilized as in the embodimentsdescribed in reference to FIGS. 3A to 3Z-4, with the further benefit ofthe distal protection filter in place. With the procedure coming to aclose, the railed sheath (26) may be retracted (60) past thestill-deployed filter (120), as shown in FIG. 8F, after which the tethermember (126) may be utilized to assist in retraction (128) of the filtermember out of the access point (110) and completion of the procedure.

Referring to FIG. 9, a railed sheath may be utilized to only partiallyprotect a route to a targeted anatomical position for a diagnosticand/or interventional instrument. For example, if the main objective isto protect the subject vessel pathway between the lower ascending aorta(130) and the access point, a railed sheath (26) may be deployed onlyacross this length, and the instrumentation (56, 54) may be advancedacross this length through the railed sheath (26), and then across theremainder of the length of the vessel to the targeted anatomy withoutthe protection and/or mechanical guidance of the railed sheath.

Referring to FIG. 10, a deployment technique is illustrated whereinsubsequent to preoperative analysis (302) and establishment of vascularaccess (304), a guidewire and/or introducer sheath may be advancedacross the access location to provide for guidance and support ofadditional instrumentation which may be advanced (306). A compressedconfiguration of a railed sheath may be advanced-for example,over-the-guidewire and through the introducer sheath-in a compressedconfiguration (308). Once the railed sheath has reached a desiredlongitudinal position (310) for the interventional and/or diagnosticprocedure, the railed sheath may be expanded or allowed to expand to,for example, accommodate passage of an advancing interventional device(such as a percutaneous valve deployment assembly) across the railedsheath to the anatomical location of interest (312). With the expandedconfiguration of the railed sheath remaining in situ, the procedure maybe conducted (314), after which the tools may be retracted (316), therailed sheath returned to a collapsed or partially collapsedconfiguration (for example, by simple proximal tensioning to partiallycollapse the railed sheath, by electromagnet-induced forced to fullycollapse the railed sheath, etc) (318), and vascular access closed (320)to complete the procedure.

Referring to FIG. 11, an embodiment similar to that of FIG. 10 isillustrated, with the exception that a folding embolic filter may beadvanced (322) and deployed (324) prior to introduction of the railedsheath (308); this filter may be reconfigured into a collapsed transportconfiguration (326) and retracted (328) before final closing of thevascular access (320).

Referring to FIG. 12, an embodiment similar to that of FIG. 10 isillustrated, with the exception that a tubular embolic filter may beadvanced (330) and deployed (332) prior to introduction of the railedsheath (308); this filter may be reconfigured into a collapsed transportconfiguration (334) and retracted (336) before final closing of thevascular access (320).

Referring to FIG. 13, an embodiment similar to that of FIG. 10 isillustrated, with the exception that after removal of the interventionaltools (316), the railed sheath may be returned to a compressedconfiguration with the help of magnet-induced loads from a magneticprobe or portion of a probe (338) before retraction using the probe(340).

Referring to FIG. 14, an embodiment similar to that of FIG. 10 isillustrated, with the exception that for railed sheath introduction, thecollapsed configuration is actively maintained using magnetic loads(342), and expansion (344) to the expanded configuration afterappropriate longitudinal advancement (310) is controllably facilitatedby controllably decreasing or removing the magnetic loads, followed byretraction of the magnetic tool (346) and advancement of theinterventional or diagnostic tools through the railed sheath (348).

Referring to FIG. 15, an embodiment similar to that of FIG. 10 isillustrated, with the exception that after vascular access isestablished (304), a proximal filter, or “distal protection device” isinstalled (350) proximally; this filter may be removed (352) afterultimate removal of the railed sheath (318).

Referring to FIG. 16, an embodiment similar to that of FIG. 10 isillustrated, with the exception that the railed sheath may be onlypartially positioned across the length of the vascular route to thetargeted anatomy (i.e., rather than protecting the entire length with arailed sheath, only a portion, such as a proximal portion, may beprotected) (354).

The rail structures may comprise various bio-compatible metals, such astitanium, alloys thereof such as Nitinol superalloy, and/or polymerssuch as polyethylene, ultra-high-molecular weight polyethylene,polyethylene terepthalate, polyoxymethylene, polytetrafluoroethylene,and co-polymers thereof.

The sheetlike member may comprise a material such as polyethylene,polytetrafluoroethylene, or co-polymers thereof.

In one embodiment, a vacuum device such as a syringe may be operativelycoupled to the configuration (for example, coupled to or integrated intoa proximal handle that forms a manual interface for inserting a railedsheath catheter), and may have an elongate distal portion that may beinserted into a deployed railed sheath catheter to vacuum away embolithat may be present.

Referring to FIGS. 18A-18J, various aspects of another embodiment of anintervention protection configuration are shown, wherein a distalportion of the delivery configuration is allowed to expand relative to amore proximal portion which may remain substantially more contracted orcollapsed. Referring to FIG. 18A, a railed sheath in a collapsedconfiguration (16) has been inserted through a diseased vessel such asaorta (2), starting with transvascular access through a portion of theassociated vasculature such as the left iliac artery (6), followed byinsertion of the instrument assembly into a position as shown whereinthe distal tip is located in a preferred location, such as adjacent anaortic valve of the patient. A proximal portion of the instrumentation,including a proximal control assembly (150) remains external to thevascular access for manipulation and control of the procedure, alongwith optional external drainage or exit of fluids or embolic or othermaterials which may collect within the instrumentation. The depictedembodiment comprises an atraumatic obturator tip (148) selected toreduce the results of impacts that such distal instrumentation may haveduring insertion and placement. Referring to FIG. 18B, without theassociated anatomy (i.e., from the illustration of FIG. 18A), theassembly may comprise a collapsed railed sheath portion (16) removablycoupled to a distal obturator-jacket assembly (168) which has anatraumatic tip (148). The obturator-jacket assembly (168) preferably iscoupled, through the lumen of the sheath and proximally out through avalved (154) port (156) defined through the tubular body assembly (164)of the proximal assembly (150), to an elongate obturator coupling member(152) which may be movably positioned through a central working lumen ofthe sheath (such as that referred to as element 24 above). The depictedproximal assembly (150) also comprises a second valved (158) port (160)which may be occupied by a portion of a sheath tip manipulationassembly, which may comprise a proximal manipulation structure or handle(162) which is coupled to a distal portion of the sheath using a movabletension-applying element such as a pullwire. In one embodiment, asdescribed below, an operator may manually manipulate, or pull, theproximal manipulation structure (162) to tension the movabletension-applying element and cause closure of the distal tip of thesheath using a hoop configuration. The obturator-jacket assembly may beconfigured to assist in temporarily maintaining a collapsedconfiguration of a distal portion of the sheath, and may be configuredto extend the full length of a particularly expandable portion of thesheath which may be expanded outward subsequent to removal of theobturator-jacket assembly (168) from its collapse restraintconfiguration as shown in FIG. 18B. For example, referring to FIG. 18C,with the sheath in a desired position relative to the associatedanatomy, the obturator-jacket assembly (168) may be advanced or urged(166) distally relative to the remainder of the sheath assembly (16,150), causing the obturator-jacket assembly (168), with its atraumaticdistal tip (148), to become released from the remainder of the sheathassembly (16, 150) with such advancement. In one embodiment, such distaladvancement causes a thin jacket-like wrapper portion of theobturator-jacket assembly (168) to become torn or fractured along apredetermined pathway (i.e., via preexisting perforations created in thejacket-like wrapper portion) in a manner that substantially releases anddecouples the underlying collapsed portions of the railed sheathassembly from the jacket-like wrapper portion (while the jacket-likewrapper portion remains firmly attached to the obturator tip 148),allowing a portion of the sheath to self-expand to an expandedconfiguration (26) as shown in FIG. 18C and the close-up view of FIG.18D. Referring to FIG. 18E, with full distal advancement of theobturator assembly (168, 152), the distal portion of the railed sheathmay be allowed to become fully expanded (26), and then the obturatorassembly (168, 152) may be pulled proximally (170) through the lumen ofthe sheath (24) and through the proximal assembly (150) where it may beremoved.

Referring to FIGS. 18F-18H, with the obturator assembly removed, thisembodiment of the railed sheath is in an expanded configuration whereina proximal portion of the railed sheath remains in a relativelycollapsed or small diameter configuration (16) as compared with theexpanded distal portion (26), which features a plurality of structuralrail members (32) configured to self expand and support a tubular orfrustoconical porous filter mesh (132) surface configured to captureparticles that may enter it, such as clots or plaque particles. In oneembodiment wherein the sheath assembly is configured for aorticdeployment, the expanded distal portion may be selected to have a lengthapproximately equivalent to the arcuate length of the subject aorticarch. The embodiment depicted in close-up view in FIGS. 18G-18H featuressix elongate structural rail members (32) which may comprise a materialsuch as a nickel titanium Nitinol superalloy; other embodiments mayfeature 4, 5, 7, 8, 9, 10, 11, 12, or more rail members (32), which maybe configured to be prominent either to the inner surface or outersurface of the expanded portion (26), and may be configured to havevarious cross sectional areas and/or positions, as in the embodimentsdescribed above in reference to FIGS. 3E-3Q. Referring to FIG. 18G, inone embodiment the most distal portion of the expanded sheath portion(26) may comprise a vessel engagement portion (172) selected to maximizephysical accommodation of local endovascular geometry and/or terrain, sothat particles moving through the pertinent vessel are biased to becaptured by the railed sheath, not diverted around it. The depictedvessel engagement portion comprises a relatively low-modulus sheetlikematerial, which may comprise a thin biocompatible polymer, coupled in acylindrical fashion to a relatively low-modulus zig-zag structure (176)intercoupled between two relatively low-modulus hoops (184, 186). Thesestructures (176, 184, 186) may comprise relatively small-diameterNitinol superalloy material, for example. A controllably collapsiblehoop (174) may be intercoupled into the distal assembly and movablycoupled to the proximal manipulation assembly (element 162 of FIG. 18B,for example) to allow an operator to pull upon the proximal manipulationassembly and cause increased hoop tension in the controllablycollapsible hoop (174), causing such hoop to controllably collapse andclose the distal assembly into a closed-distal configuration (178), asshown in FIG. 181, after which the entire sheath assembly may beproximally (180) removed out of the subject anatomy while safelycontaining the contents of the sheath assembly which may have beencaptured during deployment, such as clots and/or plaque particles. Inone embodiment, the entire expanded portion (26), such as illustrated inFIG. 18G, is a self-expanding structure, in that it is biased to expandto the expanded configuration (26) upon release of mechanical constraintsuch as the aforementioned obturator jacket. In another embodiment, onlya tip portion is a self-expanding structure, such as a tip portionincluding the distal engagement portion (172) and a distal subportion ofthe frustoconical distal portion (140) of the sheath.

In another embodiment, the removable obturator jacket covering andrestraining the underlying compressed distal portion of the sheath, suchas in the assembly of FIG. 18B, may be removed directly from the outsideusing a tensile member coupled to the outer surface of the jacket andconfigured to tear the jacket away from the underlying compressed distalportion of the sheath to allow such compressed distal portion toself-expand. In other words, rather than inserting, then retracting theobturator member to detach and remove the jacket covering from theunderlying compressed distal portion of the sheath by pulling theremoved jacket out through the working lumen of the sheath, the jacketcovering may be pulled off from the outside using a tensile member, suchas a pullwire configured to be manually and controllably tensioned froma proximal location using a handle or other tensioning fixture, coupledbetween the jacket and a proximal location accessible using the proximalassembly (150) and pulled proximally away from the sheath in a tear-awayfashion prescribed by predetermined patterning (i.e., through perforatedtear-away lines or patterns). In another embodiment, a combination ofrelease/removal from through the working lumen, and release/removal fromthe outside aspect of the sheath as described immediately above, may beutilized to fully release the sheath distal end and allowself-expansion.

In summary, as described above, the inventive protective configurationsprovide a means for conducting an intervention while also protecting theunderlying tissue and related anatomy; further, the railed sheathconfigurations assist with delivery and alignment of tools and/orprostheses which may be related to the vascular intervention.

Referring to the process flow embodiment of FIG. 19, for example, afterpreoperative analysis (302), vascular access may be established (304)and a guidewire and/or introducer may be advanced into the subjectvessel lumen (306). A protective or railed sheath may be introduced(360) and advanced (310) in a compressed configuration to place thedistal portion in a desired position relative to the subject anatomy(for example, in an aortic valve prosthesis deployment configuration,the sheath may be positioned to allow for deployment of the valveprosthesis adjacent the aortic outflow tract of the patient, as plannedpreoperatively). The protective or railed sheath may be converted to itsexpanded configuration, which may comprise advancement and thenretraction of an obturator assembly, as described above in reference toFIGS. 18A-18J, which may remove a wrapper layer or compression layercoupled to the obturator, thereby allowing the underlying sheath portionto self-expand in a manner akin to that of a self-expanding stentprosthesis (362). With the protective or railed sheath in theexpanded/deployed configuration, intervention steps may be conductedwhich involve insertion and/or retraction of one or more devices, tools,or prostheses through the working lumen defined through the sheath, withprotection provided to associated tissues by virtue of such sheathdeployment (364). Subsequently the tools may be removed (316), and theexpanded distal portion of the sheath controllably returned to a saferemoval configuration wherein at least a distal portion of the sheath iscontrollably collapsed or closed, such as by a hoop closure actuated byproximally pulling a tension or pullwire, as described above inreference to FIGS. 18A-18J (368). Vascular access may then be closedafter removal of the sheath assembly (320).

Various exemplary embodiments of the invention are described herein.Reference is made to these examples in a non-limiting sense. They areprovided to illustrate more broadly applicable aspects of the invention.Various changes may be made to the invention described and equivalentsmay be substituted without departing from the true spirit and scope ofthe invention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processact(s) or step(s) to the objective(s), spirit or scope of the presentinvention. Further, as will be appreciated by those with skill in theart that each of the individual variations described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentinventions. All such modifications are intended to be within the scopeof claims associated with this disclosure.

Any of the devices described for carrying out the subject diagnostic orinterventional procedures may be provided in packaged combination foruse in executing such interventions. These supply “kits” may furtherinclude instructions for use and be packaged in sterile trays orcontainers as commonly employed for such purposes.

The invention includes methods that may be performed using the subjectdevices. The methods may comprise the act of providing such a suitabledevice. Such provision may be performed by the end user. In other words,the “providing” act merely requires the end user obtain, access,approach, position, set-up, activate, power-up or otherwise act toprovide the requisite device in the subject method. Methods recitedherein may be carried out in any order of the recited events which islogically possible, as well as in the recited order of events.

Exemplary aspects of the invention, together with details regardingmaterial selection and manufacture have been set forth above. As forother details of the present invention, these may be appreciated inconnection with the above-referenced patents and publications as well asgenerally known or appreciated by those with skill in the art. Forexample, one with skill in the art will appreciate that one or morelubricious coatings (e.g., hydrophilic polymers such aspolyvinylpyrrolidone-based compositions, fluoropolymers such astetrafluoroethylene, hydrophilic gel or silicones) may be used inconnection with various portions of the devices, such as relativelylarge interfacial surfaces of movably coupled parts, if desired, forexample, to facilitate low friction manipulation or advancement of suchobjects relative to other portions of the instrumentation or nearbytissue structures. The same may hold true with respect to method-basedaspects of the invention in terms of additional acts as commonly orlogically employed.

In addition, though the invention has been described in reference toseveral examples optionally incorporating various features, theinvention is not to be limited to that which is described or indicatedas contemplated with respect to each variation of the invention. Variouschanges may be made to the invention described and equivalents (whetherrecited herein or not included for the sake of some brevity) may besubstituted without departing from the true spirit and scope of theinvention. In addition, where a range of values is provided, it isunderstood that every intervening value, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention.

Also, it is contemplated that any optional feature of the inventivevariations described may be set forth and claimed independently, or incombination with any one or more of the features described herein.Reference to a singular item, includes the possibility that there areplural of the same items present. More specifically, as used herein andin claims associated hereto, the singular forms “a,” “an,” “said,” and“the” include plural referents unless the specifically stated otherwise.In other words, use of the articles allow for “at least one” of thesubject item in the description above as well as claims associated withthis disclosure. It is further noted that such claims may be drafted toexclude any optional element. As such, this statement is intended toserve as antecedent basis for use of such exclusive terminology as“solely,” “only” and the like in connection with the recitation of claimelements, or use of a “negative” limitation.

Without the use of such exclusive terminology, the term “comprising” inclaims associated with this disclosure shall allow for the inclusion ofany additional element--irrespective of whether a given number ofelements are enumerated in such claims, or the addition of a featurecould be regarded as transforming the nature of an element set forth insuch claims. Except as specifically defined herein, all technical andscientific terms used herein are to be given as broad a commonlyunderstood meaning as possible while maintaining claim validity.

The breadth of the present invention is not to be limited to theexamples provided and/or the subject specification, but rather only bythe scope of claim language associated with this disclosure.

The invention claimed is:
 1. A method for deploying a device to a distallocation across a diseased vessel, comprising: a. inserting anexpandable protective sheath system comprising an obturator assemblyremovably coupled to the distal portion of a sheath into a diseasedvessel at a point of entry, the sheath defining a lumen therethrough,said obturator assembly being configured to pass through said lumen, thesheath having a collapsed configuration, wherein the sheath has a firstcross sectional outer diameter defines a first lumen inner diameter, andan expanded configuration, wherein the sheath has a second crosssectional outer diameter and second lumen inner diameter, said systemcomprising an embolic capture assembly coupled to said sheath andextending from the distal and of said sheath, said embolic captureassembly housed in said obturator assembly and comprising rail memberswhich are coupled to a tubular porous filter mesh configured to captureparticles in a blood vessel; and the distal portions of said railmembers and said tubular porous filter mesh being coupled to acollapsible hoop structure; said hoop structure having a collapsedconfiguration and an expanded configuration, said expanded configurationbeing dimensioned to engage the walls of a blood vessel; and b.advancing the sheath in its collapsed configuration through said vesseland across at least a portion of the diseased vessel to a positionadjacent the distal location without substantial size interferencebetween the first cross sectional outer diameter of the sheath and aninner diameter profile of a lumen of the diseased vessel; c. causingsaid obturator assembly to move distally away from said sheath tounhouse said embolic capture assembly, d. causing said hoop structure toexpand into its expanded configuration, whereby said hoop structurecomes into contact with the inner wall of said blood vessel lumen andsaid tubular porous filter mesh is expanded to permit blood to flowthroughout and is capable of catching particles in the blood, e.advancing and deploying a device through said sheath and said emboliccapture assembly whereby the sheath is expanded to the expandedconfiguration with incremental pushing of the device longitudinallythrough the lumen, f. causing said hoop structure to collapse after saiddevice passes therethrough thereby capturing such particles as may havebeen caught by said tubular porous filler mesh, and g. withdrawing saidembolic capture assembly and said sheath from said vessel.
 2. The methodof claim 1, wherein said obturator assembly has an atraumatic distaltip.
 3. The method of claim 1, wherein the diseased vessel is an aorta.4. The method of claim 1, wherein the device is an implantableprosthesis.
 5. The method of claim 4, wherein the implantable prosthesisis a cardiac valve.
 6. The method of claim 1, wherein said emboliccapture assembly is housed in a jacket removably coupled to said emboliccapture assembly with said jacket constraining said hoop structure inits collapsed configuration and further comprising the step offracturing said jacket to allow said hoop structure to assume itsexpanded configuration.
 7. The method of claim 6 wherein said sheathsystem comprises a proximal manipulation structure coupled to atension-applying element which is coupled to said hoop structure and iscapable of collapsing said hoop structure when placed under tension tocapture particles in said tubular porous filter mesh and furthercomprising the step of collapsing said hoop structure by pulling on saidtension-applying element.
 8. The method of claim 6 wherein saidobturator jacket is fractured by advancing a device through said tubularporous filter mesh.
 9. The method of claim 6, wherein said jacket isfractured by applying tension to a tensile member coupled to the outersurface of said jacket.
 10. The method of claim 6, wherein said jacketis fractured by self-expansion of said embolic capture assembly.
 11. Themethod of claim 1, wherein said obturator assembly is withdrawn fromsaid sheath prior to deployment of said device.
 12. The method of claim1, wherein said obturator assembly is moved proximally and removed fromsaid sheath after being moved distally to unhouse said embolic captureassembly.